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Quality of HVX / HPX in 24p vs HMC150 in 1080

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Isaac Brillant
Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 28, 2009 at 10:33:01 pm

Hi,

I'm deciding between the Panasonic HMC150 (which is AVCHD and uses SD cards) and the HPX170 (which is DVCProHD and uses P2 cards). What is holding me back from getting the HPX is the cost of P2 cards.

But I am wondering, if I were to save on card costs by shooting in 720p on the HPX (which uses about half the space as 1080 when shooting in 24p?) would that still result in better quality than shooting in 1080 on the HMC150?

I didn't see any other posts on this comparison, aside from the one I posted in the HMC150 forum as well, but if you know of any, please point me towards them

Thanks!

Isaac


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Jeff Regan
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 28, 2009 at 10:47:55 pm

AVC CAM or AVCHD codecs can look pretty good at 24Mbps, they are full sample codecs in highest quality mode, however, that advantage is not as useful for a pixel shifted CCD camera like the 150. The other issue is 4:2:0 color space vs. 4:2:2 for DVCPRO HD and the HPX170, which is the exact same front end as the 150. If doing a lot of green screen, 4:2:2 can be advantageous.

The 170 has the advantage of the simplicity of editing with DVCPRO HD,
which isn't as processor intensive, variable frame rates for off-speed shots, Native frame rate modes so that a 32Gb card can record for over 80 minutes in 720/24PN. HD SDI is also useful for professional monitors, which the 150 lacks.

Jeff Regan
Shooting Star Video
http://www.ssv.com


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Isaac Brillant
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 28, 2009 at 11:21:07 pm

Thanks Jeff, for the helpful info. I hadn't thought too much about the back-end issue of output and editing. I had assumed I'd transcode the AVCHD to something FCP can work with, but that may be a pain.

So, as far as image quality goes, do you think that having 4:2:2 color space, and having a higher data rate of 50mb/s vs 24 mb/s contributes more to the quality of the image than the extra resolution?

I wonder if you took a 720 x 960 HVX image and enlarged to 1080 x 1920 and compared it side by side with HMC150's 1080, what it would look like. I've looked for comparison pics online, but these images are already compressed for the web so it doesn't help much.

Also, regarding the HMC150 "pixel shift" you mentioned, does that mean than 1080 x 1920 on the HMC isn't "really" 1080?

I don't totally understand how the resolution works with these cameras, but I read somewhere that each chip on HMC150 is 960 x 540 pix, and that this "amounts to a resolution of about 1440 x 810."

This sort of confused me. Because then it seems like I'm really comparing 960 x 720 vs 1440 x 810, rather than 1920 x 1080, which is a much smaller difference.

Thanks very much
Isaac

PS - While we're talking resolution, why are some of these cameras 1080 x 1440 (like my Canon XHA1s) and some are 1080 x 1920 (like the HMC150)? They both look like the same aspect ratio so how does that work out? Thanks again Jeff




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Trevor Ward
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 28, 2009 at 11:49:58 pm

I can answer that last question. 1440x1080 doesn't use square pixels. It's pixels are wider than square, so each pixel is covering more ground. What that means is that you're not really getting 1920 lines of resolution. The codec compensates for this and does some math so that it doesn't have to record as much information. So, if you're image is in the shape of a football field, both resolutions are recording the length of the football field. The 1920 records 1920 small slices of the field. The 1440 records 1440 slightly bigger slices of the field.

The HPX 500 and HVX 200 do this.

Overall, all these cameras are going to have a great image when looking at a well lit image. I've seen the local news channels shooting with 150's. Where they start to separate from each other is in optics and latitude. The smaller chip cameras will not give you as big of a range going from highlights to blacks. They are noticeable different. Also, the optics for the bigger cameras are much better and give you a better depth of field and cleaner image.

I own a 150 and it has a super wide lens and the images look great. However, I'm a bit disappointed with the depth of field that I'm able to get.

-trevor ward
Red Eye Film Co.
http://www.redeyefilmco.com
orlando, fl


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Jeff Regan
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 28, 2009 at 11:55:46 pm

Isaac,

Don't use bit rate as a quality comparison because DVCPRO HD is a DCT based codec that is much older and less efficient than an h.264 AVC codec. DVCPRO HD at 720/24PN runs at 40Mbps, not 100Mbps anyway.

What you get with a full sample codec is better resolution if the front end of the camera can actually produce a full raster image. The CCD's in an HVX200/A, HPX170, HMC150 are pixel shifted, doubling the pixel count from 540X960 to 1080X1920, in theory. However, this does not have the true resolution as a full raster sensor. But, you are recording more samples horizontally with square pixels with AVC HD vs. rectangular pixels that sub-sample 1080X1920 down to 1080X1280 in the case of DVCPRO HD, just as HDCAM sub-samples to 1440.

Some of the lack of color space in a 4:2:0 codec can be replaced by a full sample codec, but the real detail has to exist in the first place.

I haven't done side by side testing of the 150 and 170 because the 150 doesn't do enough of what I want, and I already had 2/3" DVCPRO HD cameras, so the 170 made more sense as a B-camera.

Ultimately you need to decide on which workflow works best for you, whether you want to spend $600 per 32Gb P2 card, if the off-speed capabilities of the 170 are important and what kind of monitoring you have.

If you want the most possible resolution, then an HPX300 is the best choice, and twice the dollars, of course!



Jeff Regan
Shooting Star Video
http://www.ssv.com


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Isaac Brillant
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 12:00:20 am

Thank you both.


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Trevor Ward
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 1:14:38 am

Aha, yes. The 300 is nice, is a shoulder mount camera and has interchangeable lenses. But the 300 has smaller chips AND it's CMOS, which many people object to.

-trevor ward
Red Eye Film Co.
http://www.redeyefilmco.com
orlando, fl


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Isaac Brillant
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 1:34:39 am

What about the GY-HM700U ?

With some sort of attachment, that can shoot in XDCamEX at 35mbps. Or is that bit rate also not comparable because its a different codec?

I posted this question somewhere else, but since you're here : ) ....


How would you order these codecs in order of image quality, storage space aside, and all other things being equal:

- XDCamEX - 35mbps
- XDCamHD (same?)
- HDV (mpeg2) - 25 mbps
- AVCHD (mpeg4) - 24 mbps
- DVCProHD - 35 mbps
- Whatever codec JVC uses when recording to SD cards, when not using XDCam. HDV?




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Trevor Ward
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 1:48:03 am

Honestly I'm not a codec expert. I went crazy this year in comparing cameras and whatnot. It's really hard to say "All else being equal." because it's not. It's completely irrelevant to compare just codecs because there's so much more that goes into the quality of the image.

About the best you can do is look at still images from different cameras and see the differences.

I will say, in my limited research, the HDV image is probably the lowest quality image you'll see. However, HDV cameras are consistently being used as b-cameras and even a-cameras for broadcast television.

I'd look at budget and workflow and specific needs above all else.

-trevor ward
Red Eye Film Co.
http://www.redeyefilmco.com
orlando, fl


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Jeff Regan
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 1:52:32 am

HPX300 has 1/3" sensors, as does HMC150/HPX170, only CMOS full raster vs. CCD pixel shifted. HPX500 has 2/3" CCD's, pixel shifted, DVCPRO HD only, no AVC-Intra 50 or 100.

JVC 700 is HDV based, so MPEG2 Quicktime files or optional XDCAM EX, both are Long GOP 4:2:0, same as AVC CAM(AVC HD). DVCPRO HD offers Native frame rates, 4:2:2, I-Frame frame structure, but is sub-sampled to 960 and 1280 horizontal for 720 and 1080 resolutions.

JVC 700 uses 1/3" CCD's, pixel shifted vs. native HD sensors.

I would rather buy an EX1(well, actually I do have an EX1) than a 700 because it has 1/2" full raster CMOS sensors, SxS card XDCAM EX is built-in. It is quieter and better in low light than any of the other cameras, but has CMOS artifacts, lousy ergonomics.

If Panasonic came out with a large sensor(1/2" or bigger)camera with AVC-Intra 100 for under $10K, it would be a giant killer. HPX300 is not as good in low light, noisy, deep depth of field compared to EX1 or other larger sensor cameras.

Jeff Regan
Shooting Star Video
http://www.ssv.com


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Isaac Brillant
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 2:39:53 am

Hi Jeff

What do you mean by "Native frame rates" for the HPX? What does it mean if it's not native (as is the case with the other 2 cameras?) ?

When you say that JVC 700 uses 1/3" CCD's, pixel shifted vs. native HD sensors...
that's the same with the HPX and HMC150 right?

Thanks again
Isaac


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Jeff Regan
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 5:13:46 am

Isaac,

Native frame rate mode means that the camera is only recording the actual frames needed, ie; 24 frames or 30 frames vs. 60 frames with redundant frames to make a 2:3 pulldown or 2:2 pulldown. Native mode gives you 2.5 minutes per Gb in DVCPRO HD or AVC-Intra 100 in 720/24P vs. 1 minute per Gb in non-Native mode.

Yes, JVC 700, HVX200/200A, HPX170, HPX500 are pixel shifted CCD sensors vs. HPX300 or EX1/3 CMOS full raster sensors.

Jeff Regan
Shooting Star Video
http://www.ssv.com


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Ronald Wilk
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 2:55:46 am

Just happened across your post and was a tad confused by your mention of the HPX 300 being noisy... did you mean to imply in low light situations, whatever that means? Given that "low Light" can be defined differently by different people. Just as an aside, I own an HPX 300 (and an HPX 170) and with the next to most recent firmware(9.30) I do not find it noisy at all. Further more, I do not find it to be any noisier in poorly lit situations than my recently sold EX3. That said, the EX3 was 1/2 to 1 stop more sensitive than the 300 likely attributable to the 1/2" chips. I wonder, do you own an HPX300?



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Jeff Regan
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 5:09:57 am

Ronald,

I mean compared to a 2/3" camera, the HPX300 will be slower and to get back to the same sensitivity to even the EX1 or EX3, much less a good 2/3" HD camera, you'd have to boost gain.

I've only spent about an hour with an HPX300, but find it to be about the best 1/3" camera I've seen, especially factoring in AVC-Intra, but there's only so much 1/3" imagers can do in the trade off between sensitivity and noise.

I wish Panasonic would offer -3db in their lower end cameras to reduce noise if wanted--I most often shoot with my HDX900 and HPX2700 in -3db. Of course, these cameras are very sensitive, so the -3db setting isn't a big deal.

Jeff Regan
Shooting Star Video
http://www.ssv.com


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Ronald Wilk
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 3:45:14 pm

Hi Jeff:

First off, allow me to address your lament, in re gain. The HPX 300 does indeed have a -3db gain setting and I keep the "low" gain set to that position 90% of the time.

As for the sensitivity difference between EX3 and the 300, in my comparison, the difference is no more than 1/2 to barely a whole stop in favor of the EX, hardly enough to quibble over in most situations and not enough to promote a noise differential. Frankly, I am not a fan of the Sony Ex "look" and when you couple that with the terrible ergonomics of the Ex series, the value of the 1/2" chip fades quickly, IMO. And that, coupled with the bevy of accessories required to make the camera just barely ergonomically acceptable and or the costly external device required to improve upon its data rate, are what prompted me to sell the Ex3 in favor of the 300, a decision that established its righteousness from the moment that I opened the box.



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Dan Brockett
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 5:11:13 pm

Hi Ronald:

Great explanation of the positives and minuses of the EX1/EX3. They are great cameras and are totally capable of creating arresting images. BUT, the 300 is a superior package to either IMHO. The difference between the 1/2" sensor and 1/3" sensor is not as great as people make it out to be and the ergonomics, feel and codec of the 300 blow away the Sonys.

Dan

Providing value added material to all of your favorite DVDs


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Jeff Regan
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 5:44:40 pm

There is an informal review of the 300, EX1, JVC700 and Canon 5D in last month's ICG Magazine, it was non-technical and didn't get into the codecs. The 300 was chosen for the best ergonomics, form factor, good resolution, color, but was found to be the worst in low light. The JVC 700 did nothing that set it apart other than the convenience of QT file recording. The EX1 "punched above its weight" in image quality terms, according to them. The Canon 5D didn't outdo the video
cameras except in low light ability and had the usual aliasing on the edges, worse ergonomics than the EX1.

The 300 has the best codec by far, in my opinion, but the EX1 is fast and clean at the front end. I'm glad the 300 has -3db, I had forgotten that, since my tests were trying to get my Letus Ultimate 35mm adapters to work with the stock Fuji lens vs. a true test of the camera.



Jeff Regan
Shooting Star Video
http://www.ssv.com


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Ronald Wilk
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 6:14:00 pm

Couldn't agree more in regards to your EX sentiments. Most of the derogatory comments that I have read in re the HPX300 have been from people repeating third party opinions rather than actual owner/users. After all, there are some intensely obvious biases put forth by Sony owners, some of whom actually admit to their bias, so, a grain of salt is required in those instances. In my case, I have had ample time to compare the two, having owned both at the same time (EX3 and 300) and having discarded the Ex3. That's not to say that the EX3 did not produce wonderful images but for my purposes its negatives more than outweighed its positives.

But I have another pet peeve, and that refers to the phrase, "low light." How does one determine where low light begins and ends? IMO it's a meaningless attempt to describe a lighting environment and probably should be supplanted with something more quantifiable. From my perspective it's almost like trying to describe the intensity of a specific hue without using actual, reproducible values but enough of my rant.




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Jeff Regan
Re: Quality of HVX / HPX in 24p vs HMC150 in 1080
on Dec 29, 2009 at 9:00:21 pm

Ronald,

Agreed, "low light" is not a technical descriptor. ASA or EI numbers are better. This changes depending upon resolution and frame rate, shutter speed, gain setting and ND of course.

It does seem that CMOS offers very good sensitivity, a bit better than CCD given the same sensor size and pixel sites.

I find my EX1 to be pretty close to my HPX2700 in 720/24P, but is slower in 1080/24P. My HPX170 is much slower with the same settings.

Jeff Regan
Shooting Star Video
http://www.ssv.com


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marwan faraj
panasonic hj p2 2100
on Sep 10, 2010 at 8:38:41 pm

I want to know some information about the camera panasonic hj p2 2100
And pixels????


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